My perspective is utilitarian. I'm a hummingbird photographer, and I love hummingbirds. So, first things first:
Hummingbird health. The most important thing is to clean the feeder frequently and thoroughly. The mold that grows in nectar is toxic to hummers, and hummers will learn not to come to a contaminated feeder. So for the birds health, and for their nutrition, you must clean them thoroughly as frequently as every 2 days when it is hot, and every 3 when it is warm. The kind of feeder you show is quite difficult to quickly clean on the inside.
That kind of feeder does not have an ant moat, and that can be a problem.
They are ornamental, but even the prettiest feeder is still ugly compared to the hummingbird itself. If you are interested in photographing the bird, a saucer style feeder with built in ant moat, and needing no bee guards is excellent. I recommend cutting off the perch, so that you can photograph the bird while the hummingbird is hovering a few inches away, as they typically do between sips.
Here is a photo of such a saucer feeder, where the violet crowned hummingbird is NOT in posed hover position, but sipping. I cover all but one of the feeder ports, so that it will be easier to get a shot from the angle I want, without the feeder in the shot. See the link below
http://www.gregscott.com/post/20100419_0738_100_0750_gjs.jpg
More trouble to maintain is an inverted bottle style feeder. This needs a secondary ant moat, and forget the bee guard, the yellow actually attracts bees and wasps, and the bee guard grate holds nectar drips which makes it easier for the bees to find the nectar. It needs bottle brushes and tiny brushes to clean the tube.
All feeders should be hung high, or cats WILL learn to eat your birds.
Visit my 2 hummingbird galleries to see 80+ high resolution hummingbird photos.
http://gregscott.artistwebsites.com